On the occurrence of very low frequency (VLF) electromagnetic radiation and its relation to some important physical conditions of the atmosphere

Abstract

SummaryContinuous recordings of VLF electromagnetic radiation were statistically compared with physical conditions of the atmosphere. The VLF level is closely associated with the distance to thunderstorms and therefore related to the dynamical weather processes. In agreement with previous studies, we found that the movement of the VLF sources is associated with the frontal system and especially with the passage of cold fronts. The VLF level is increased mainly by cold fronts of the anatype. The rainfall intensity is closely correlated to the electric discharge formation and thereby also to the VLF activity in the anafronts, while the katafronts often give rise to slight precipitation and few flashes of lightning. The atmospheric pressure changes accompanying the anafronts are largely correlated with the VLF level and the precipitation intensity. The mean diurnal and annual variations of the VLF level are determined by the occurrence of lightning activity. During the summer the daily trend is pronounced due to the insolation effect. The present study shows that the VLF level is determined to a high degree by fairly well defined areas with lightning discharges, which can be localized with automatic lightning location systems or forecasted by the weather services.

Differential flight activity among karyotypes: daily and weather-induced changes in chromosomal inversion polymorphism in natural populations of Drosophila subobscura

“…Both Jungen's results and my own, which are shown in Figure 3, indicate that D. subobscura might be influenced by a climatic factor which announces weather disturbances in advance. Such information can be obtained from the so called atmospherics, which have a range of several 100 km and whose level is closely associated with thunderstorms and cold fronts (Bergh & Israelsson, 1984).…”